Train braking system



Oct. 24, 1939. E, HEWITT TRAIN BRAKING SYSTEM Filed'i'eb. KS, 1935 3Sheets-Sheet l WINK .U

INVENTOR ELLIS E HEWETT Oct. 24, .1939. E. E. HEWITT I TRAIN BRAKINGSYSTEM 3 Sheets-Sheet 2 Filed Feb. 13, 1935 INVENTOR ELLIS E. HEWITTATTOREY Mm n M3 Mk \Q wa mm\ mm N mi.

km NW a WW Oct. 24, 1939.- E 5 gw 2,177,527

TRAIN BRAKING SYSTEM Filed Feb. 13, 1935 h 3 Sheets-Sheet 3 INVENTORELLIS EHEWITT BY%W ATTORNEY Patented Oct. 24, 1939 1 UNITED STATESPATENT OFFICE Ellis E. Hewitt, Edgewood, Pa., assignor to TheWestinghouse Air Brake Company, Wilmerding, Pa., a corporation ofPennsylvania 7 Application February 13, 1935, Serial No. 6,360 v 18Claims. (Cl. 303-24) This invention relates to a train braking. system,and in particular to a train braking system of the type employing meansfor preventing the maximum ,rate of retardation produced by anapplication of the brakes from exceeding a chosen value. 1

vThe maximum braking force which may be applied to the wheels of arailway vehicle is limited by the adhesion between 'the' vehicle wheelsand track rails. If too great a braking force is applied, the wheels maybe caused to slide even at fairly high speeds. Again, if the initialbraking force is below that which will cause the wheels to slide at highspeeds, the

' wheels still may slide as the speed of the vehicle because thecoeflicient of friction between the rubbing parts of a friction brakeincreases as the speed of the vehicle decreases, and as a consequencethe braking effect on the wheels increases. If initially high,therefore, the braking force must be decreased as the speed of thevehicle decreases, if sliding of the wheels is to be prevented,

There have heretofore been proposed a number of devices,commonlyreferred to as retardation controller devices, for reducing thebraking force as the speed of the vehicle diminishes. These devicesemploy an element operated according to the rate of retardation, andequipments having these devices employ means responsive to operation ofthis element at some chosen rate of retardation for releasing the brakesuntil the rate of retardation will have dropped below this chosen value.

As'far as I am aware, most of the means which operate responsively tothis element depend upon the sequential operation of certain parts. Ifone of the parts in the sequence should fail to operate, then thereleasing action of the brakes will not take place. It would thereforebe highly desirable if the means responsive to operation of the inertiaelement comprise dual mechanisms, each of which would be operable toeffect a release of -the brakes independently of the other, so that ifone mechanism should be inoperative, the other would be operative toeiiect the release. I

It is a principal object of the present invention to provide a brakesystem in which the maximum degree of brakingis positively limited tothat which will not-produce a rate of retardation-substantiallyexceeding a chosen value. ,-It is a further object of the invention toprovide a brake system employing a retardation controller device inwhich both pneumatic and electrical 'meansare employed to operateresponsively to operation of the retardation controller device toprevent the rate of retardation due to braking from exceeding a chosenmaximum value.

I A still further object of the invention is to provide a brake systemof the character just referred to in which indicating means are providedfor indicating operation of the electrical means referred to.

A yet further object of the invention is to provide'abrake systemembodying a novel and improved arrangement of parts for accomplishingthe above set forth objects.

Other objects and advantages of the invention will appear more fullyfrom the description which-follows, which has been taken in connec-.tion with the attached drawings, wherein,

Figure 1 is a view showing a schematic arrangement of apparatuscomprising one embodiment ofthe invention, the parts being shown foronly the head end car of a train.

. Figure 2 is a diagrammatic view of the control valve device shown inFigure 1.

Figure 3 is a diagrammatic view of the brake valve. device shown inFigure 1.

"Figure tie a diagrammatic view of the retardation controller deviceshown in Figure 1.

In Figure 1 sufficient apparatus has been shown only for the head end orcontrol car, but it will be obvious from the following description, thatby duplication of certain of the parts shown in Figure 1 on succeedingcars in the train, that the system. applies for a train of any number ofcars.

Considering briefly at first the schematic arrangement shown in Figure1, there is provided a control valve device ID for controlling thesupply of fluid under pressure to and its release from one or more brakecylinders 12. For controlling all applications of the brakes, whetherservice or emergency applications, there is provided abrake valve deviceM.

For preventing the rate of retardation produced by braking fromexceeding a chosen maximum value, there is provided a retardationcontroller devicelii. For indicating to the operator the functioning ofcertain electrical devices in response to operation of the retardationcontroller device 16, there are provided two indicating devices 18 and20.

. Considering now more in detail the parts above referredto, the controlvalve device comprises a relay valve section 22, a left hand magnetvalve section 24, a triple valve section 26, a pneumatic cut-oft andrelease valve section 28, an inshot valve section 30, and a right handmagnet casing having disposed therein a valve 36 for controllingcommunication between a passage 31 connected to a supply reservoir 38,by way of pipe 39, and a chamber 46 connected to the brake cylinder orbrakecylinders l2, by way of pipe and passage 4!. The valve 36 is'urgedtoward a seated position by a spring 42, and is adapted to be urgedtoward an unseated position by pres- 7 sure exerted on a stem 43.

Disposed in the chamber 40 is" a'slide valve 45 for controllingcommunication between the chamber 49 and the atmosphere, by way of anexhaust port .46. 45 and for exertingpressure on the valve stem 49 tounseat the valve'96, there is provided a piston 47 disposed in a pistonchamber 48. The piston 4'! is provided with a stem 49 having elementsassociated therewith adapted to engage the slide valve 45 after a lostmotion movement of the piston. Integral with the stem 49 is a guidingpiston 50, which slides in a bore to guide the movement of the piston41. The guiding piston 50 is apertured at 52to provide communicationbetween the chamber 49 and a chamber 53 above the piston 4'1. j I

The 'left'hand magnet valve section '24 is provided' with an applicationvalve 56 and a release valve 5?, which control, respectively, the supplyof fluid under pressure to and its release from the relay piston chamber48; The application valve 56 is urged toward seated position by a spring58 and toward unseated position'by action of an electromagnet in theupper part of the casing, which when energizedactuates the valvedownwardly. When the application valve is unseated, fluid 'underpressure may flow from a lower chamber 59, connected to a source offluid under pressure, to an upper chamber 60 which leads to the relaypiston chamber 48, as-will appear more fully presently.

The release valve 51 is urged toward a seated position by a spring 6!and toward an unseated position by action of another electromagnet inthe upper part of the casing, which when energized actuates the valvedownwardly. When the application valve 56 is seated and the releasevalve 5'! is unseated, fluid under pressure is released from the pistonchamber 48 to the atmosphere by way of unrestricted exhaust port 62.

The triple valve section 26 is provided for also controlling the flow offluid to the relay piston chamber '49, and is embodied in a casinghaving a slide valve chamber 63 and a piston chamber 64. Disposed in theslide valve chamber 63 is a main slide valve 65'and a graduating valve66.

isposed inthe piston chamber 64 is a piston 61 for operating the twoslide valves.

The piston 61 is provided with a stem 68, which is recessed 'to receivethe graduating slide valve 66 so as to move the graduating valvecoextensive with movement of'the piston 61, and which is also providedwith a collar adapted to engage the main slide valve 65 after a lostmotion movement of the piston.

The slide valve chamber 63 is in constant communication with anauxiliary reservoir 12 by way of pipe and passage 13, while the pistonchamber 64 is in communication with a brake pipe 14, by way of pipe andpassage I5.

For actuating the slide valve" When a service reduction in brake pipepressure is effected, the piston 67 moves upwardly until it engages agraduating stem l6 where it is ingvalve B3, so as to move the graduatingvalve coextensive with movement of the piston 84, and also havingelements associated therewith adapted to engage the main slide valve 82after a lost motion movement of the piston 84.

The piston 84 is urged to an uppermost position by a spring 86, and isadapted to be actuated to a lower position upon a reduction' of pressurein the piston chamber 8!. The piston chamber BI is connected to acontrol pipe 88 by way of pipe and passage 89.

The pneumatic cut-off and release valve section 28 controlscommunication from both the left hand magnet valve'section 2d and thetriple valve section 26 to the relay piston chamber 48, and alsocontrols communication from the relay valve piston chamber 48 to theatmosphere, by

way of a safety valve device as. This safety valve device is preferablyone of the types commonly employed in connection with fluid pressurebrake apparatus, the function of which, as is well known in the art, isto prevent the release of fluid under pressure from the volume connectedthereto below a predetermined value of pressure.

The inshot valve section 39 is embodied in a casing having a ball valve92 disposed in a ball valve chamber 93 and adapted to control comemunication between the ball valve chamber and a passage 94. Theballvalve 92 isurged toward an 'unseated position by engagement therewith ofa-stem 95 associated with a piston 96 disposed in a piston chamber 91.The piston 96 is urged upwardly to cause unseating of the ball valve 92by a spring 98 disposed in a spring housing 99. The right hand magnetvalve section 32 is embodied in a casing providedwith a. supply valve I99 and a release valve [9 l. The supply valve I90 is adapted tocontrolthe supply of fluid under pressure by one communication to thepneumatic cut-off and release valve piston chamber BI and therelease'valve I9! is adapted to release fluid under pressure from thepiston chamber 8| regardless of how supplied to the piston chamber. Thesup-ply valve I99 is urged toward seated position by .a spring 92 andtoward unseated position by action of an electromagnet in the upper partof the casing, which when energized actuaglcs the supply valvedownwardly. The re lease valve Hill is urged toward a seated position byanother spring Hi3, and toward an unseated position by action of anotherelectromagnet in the upper part of the casing, which when energizedactuates the release valve downwardly.

When the supply valve Hill is unseated, a comthe piston chamber 8l. Whenthe supply valve I09 isseated, and the release valve i0! is unseated,this communication tothe maintaining reservoir I06 is cut off and fluidunder pressure is released from the piston chamber 8Itothe" atmosphere,by way of restricted exhaust port I09.

The brake valve device I4 is embodied in a casing having mountedtherewithin and insulated therefrom a stationary release contactIIZ anda stationary application contact I I3. For engaging these two contacts,respectively, .there are provided a movable release contact'H4 'and'amovable application contact H5. The twomov able contacts are carried oneither; end oi an insulating and carrying member H6, which is pivotallymounted intermediate its ends at IN to a plunger H8 having one endthereof 'slidably disposed in a bore I I9 in the casingn Two springs I20and I22 act upon the carrying member H6, on either side of the'pivot'H1,to

, urge the two movable contacts H4 and I15 upwardly. When the carryingmember' I I6 is'thus urged upwardly, the movable release contact H4engages the stationary release contact I I2, while the end of thecarrier H6 to which the movable application contact H5 is securedengages an adjustable stop I23. v I

When the plunger H8 is actuated downwardly, the spring I22, which isweaker than thespring I20, yields first, so that movablereleaseic'ontact H4 disengages from stationary release contact H2, andwhen the right end of the carrier H6- has been actuated downwardly farenough to engage a lug I24, the left end ofthe carrier 1 I6 thencompresses the spring I20 and movable ap} plication contact H5 thenengages stationary application contact H3. The purpose of this operationof these contacts will appear more fully in the description of operationof this embodiment. v

For actuating the plunger H8 downwardly, there is provided an actuatinglever I26, which has its right end pivotally secured to the upper end ofthe plunger H at I21, and its left end terminating in a finger I28bearingupon a cam I29 under pressure of a spring I30.

Intermediate its ends the actuating lever I26 is pivotally secured atI3I to a stem I32 associated with a piston I34 disposed in a pistonchamber I35. The piston I34 is urged downwardly by a spring I36, whichis to be understood as re quiring greater force to compress it thanre-': quired to compress the combination of the aforementioned twosprings I20 and I22. Therefore, as the cam I29 is rotated and the fingerend I28 of the actuating lever I26 raised, thelever will fulcrum aboutthe pivot point I3I to disengage contact I I4 from contact H2 and toengage contact H with contact I I3, as before described.

The piston chamber I35 is in communication with a straight air pipe I58,and when fluid under pressure is supplied to the piston chamber fromthis pipe, the piston I34 will be moved upwardly to actuate the leverI26 about its left end. I28, for a purpose and in a manner to be morefully described presently. q

The cam I29 is secured to a shaft I40 which is rotatable by a handle I4Isecured thereto and having a notching pin I42 adapted to engage notchesin a quadrant ring I44.

Disposed in a rotary. valve chamber I45, in-a lower part of the brakevalve device casing, and operable according to rotation of theaforementioned shaft I40, is a rotary valve I46. This valve is held uponits seat by-a spring I41; and

controlsbommunications to be more fully described hereinafter.

The valve chamber I45 is in constant communication with a feed valvedevice I48, by way of pipe and passage I49. The feed valve device I48 ispreferably of one of the types commonly employed, and, as is well knownin the art, functions to maintain a predetermined pressure of the fluidsupplied to the volumes connected therewith. The feed valve device is inturn connected to a main reservoir I50, which may have fluid suppliedthereto under pressure by any of the compressor means commonly employedin the art;

The retardation controller device I6 is embodied in' a casing having aninertia responsive body'l52 slidabl upon surfaces I53 and I54 in alinear pathway. The retardation controller device is positioned upon thehead end or control car ina manner such that when the brakes are appliedand the vehicle or train decelerates, the body I52 is actuated by theresulting force of inertia towards the left, as viewed in Figure 4.

When moving to the left, the body I52 engages a roller 15.5 secured toan upper bifurcated end of a lever I56, and rotates the lever I56 in acounterclockwise direction about a pivot I51. When the lever is thusrotated, another roller I58 secured between other bifurcations of thelower end of the lever engages a slide valve I60, and actuates theslide'valve to the right against opposition of a spring I6I, whichnormally urges the slide valve and body I52 to biased positions to theleft and right, respectively.

Secured to and insulated from the lever I56 are two contacts I63 andI64, connected together by a connector I65. When the lever I56 isrotated in a counterclockwise direction by the body I52, the firstcontact I 63 is actuated to disengage from a coacting stationary cut-offcontact I66, while the other contact I64 is shortly thereafter actuatedinto engagement with stationary release contact I61. The two stationarycontacts I66 and I 61 are secured to and insulated from the retardationcontroller device casing by an insulating member I68.

Since the force of inertia resulting during deceleration of the vehicleor train is proportional to the rate of deceleration, it follows thatthe movement of body I52, and hence the degree of rotation of the leverI56 and the degree of movement of slide valve I60, are proportional tothe rate of deceleration. The opening and closing of the contactsdescribed and the control of communications by the slide valve I60 to bedescribed later, may therefore be caused to take place at predeterminedrates of deceleration.

The operation of this embodiment of my invention will now be describedwith reference to one car only, and it will hereinafter be pointed outhow the adaptation to a train comprising more than one car may beeffected.

Running condition When the vehicle is running the handle I4I of thebrake valve device I4 is maintained in release position. In thisposition the parts 01 the brake valve device will be in the positionsshown in Figure 3.

In release position of the brake valve device, the rotary valve I46connects the feed valve device I48 to the brake pipe 14, through acommunication which includes, beginning at the feed valve device, pipeand passage I49, rotary valve chamber I45, rotary valve port I10, and

passage I II connecting with the brake pipe. The brake pipe will thusbemaintained charged to feed valve pressure.

With the brake pipe thus maintained charged,

' the supply reservoir 38, the auxiliary reservoir 12,

and the maintaining reservoir I06, will all be charged to brake pipepressure. Communication from the brake pipe to the auxiliary reservoiri2 is by way of pipe and passage 15, triple valve piston chamber 64,feed groove I I2, slide valve chamber 93, and pipe and passage I3. Thesupply reservoir is charged from the brake pipe by way of pipe andpassage 15, chamber 64, past check valve 599, and passage ll'I, althoughit may also be charged from the auxiliary reservoir, by way of checkvalve device I13, which permits the flow of fluid from the auxiliary tothe supply reservoir, but prevents flow in the opposite direction. Themaintaining reservoir I06 is charged from the supply reservoir, by wayof check valve device I'I l, which permits fiowof fluid from the supplyreservoir'to the maintaining reservoir, but prevents flow in the reversedirection.

With the brake pipe thus maintained charged, triple piston Bl will be inthe lowermost position shown in Figure 2, where it will be noted that avolume reservoir I15 is connected to the atmosphere, byway of pipe andpassage I19, cavity I'll of slide valve 65, and exhaust port I18.

In release position of the brake valve device I4, the movable releasecontact H4 engages stationary release contact H2, and as a result theelect'romagnet controlling the-release valve 5'! in the left hand magnetvalve section 24, of the control valve device I0, will be energized froma battery I through a circuit which includes, beginning at the battery,conductors I8I and I92, contacts II2 and II l, and conductor I83, the return circuit to the battery being by way of ground connecting I84. I

In the retardation controller device I6, the body I52 will besubstantially in the position shown in Figure 4, and contacts I63 andI95 will be in engagement. As a result, the electromagnet controllingthe supply valve Illil in the right hand magnet valve section 32, of thecontrol valve device 69, Will be energized from the battery I80, througha circuit which, beginning at the battery,

includes conductor I3 I, contacts I53 and I56, con

ductor I85, the electromagnet, conductor I86, jumper I9? at the rear endof the vehicle (or train), conductor I88, the winding of a relay I89,and ground connection I 99.

Also, slide valve I of the retardation controller will maintain acommunication between the maintaining reservoir I06 and piston chamber8|, by way of pipe 296, slide valve I69, pipe 88, and pipe and passage89.

With the release valve 51 in the left hand magnet valve section 24 andsupply valve I06! in the right hand magnet valve section 32 bothunseated, and slide valve I60 in its biased position, the parts of thecontrol valve device I0 will be in the positions shown in Figure 2. Therelay valve section 22 will then hold the brake cylinder or brakecylinders I2 in communication with the atmosphere, and the brakes willbe held released.

Service application When it is desired to effect a service applicationof the brakes, the handle MI of the brake valve device I9 is movedthrough the service zone to a degree in accordance with a desired degreeof braking. This movement of the handle will rotate the cam I 29, and asa result the left end I28 of the actuating lever I26 will be raised, thelever. fulcrumingv about the pivot I3I. Spring I36 may or may not becompressed 'depending on the degree of movement of brake valve handleMI. The right end of the lever E20 thus actuates the plunger 8downwardly to cause movable release contact II4 to disengage fromstationary release contact II2, and to then cause movable applicationcontact II5 to engage stationary application contact II3.

Disengagement of contacts H2 and H t opens the circuit previouslydescribed to the electromagnet controlling release valve 51, and therelease valve is then actuated to seated position by its spring BI.

Engagement of the two application contacts H3 and H5 causes energizationof theelectromagnet controlling the application valve 59, in the lefthand magnet valve section 24 of the control valve device I0, from thebattery I89, through a circuit which includes, beginning the battery,conductors I 8| and I92, contacts H3 and H5, and conductor I92, thereturn circuit to the battery being by way of the aforementioned groundconnection I84. The application valve 56 is thus unseated, and fluidunder pressure flows from the supply reservoir 39 to the relay pistonchamber 48, through a communication which includes, beginning at thesupply reservoir, pipe 39, passage 3i, passage 59d, past the unseatedapplication valve 56, passage I95, and double check valve chamber I99,where double check valve I9I'is actuated to the upper position.

From the double check valve chamber I thefiow to the relay pistonchamber 93 is through from thence to relay piston chamber 98, by way ofpassage 200. The other branch from the double check Valve chamber I955includes passage 20I, slide valve port I99, slide valve chamber 89, andpassage 202, which connects with the aforementioned passage 200 leadingto piston chamber 48. l

Relay piston 41 is actuated upwardly by the supply of fluid underpressure to chamber 48 and after a delayed movement it actuates slidevalve 45 to blank exhaust port 46, and thereafter the upper end of stem49 engages the valve stem 49 to unseat the valve 36. Fluid underpressure then flows from the supply reservoir 39 to the brake cylinderor brake cylinders ill, by Way of pipe 39, passage 31, past the unseatedvalve 36, slide valve chamber 40 and pipe and passage As the pressure inrelay piston chamber lt builds up, a pressure will be reached where theinshot piston 96 will have been actuated downwardly far enough to seatthe ball valve 92.

from whence the communication includes passage 203, cavity 294 in slidevalve I55, passage 205, and pipe 206. Fluid under pressure in thestraight air'pipe flows to the piston chamber I35 in the brake valvedevice I 4, where the piston I34 is actuated upwardly.

When the piston I34 has been actuated upwardly far enough to causemovable application contact I I to disengage from stationary applicationcontact N3, the electromagnet holding unseated the application valve 50,in the control valve device I0, will be deenerglzed and the flow offluid from the supply reservoir 88 tothe relay piston chamber 48, andstraight air pipe I38, will be cut off when spring 58 seats theapplication valve 56.

The supply of fluid under pressure from the .supplyreservoir to thebrake cylinder will continue until the pressure in relay valve chamber53, above relay piston 41, is substantially the same as the pressure inpiston chamber 48, Whereupon the piston 41 will move downwardly untilvalve 36 is seated and the supply to the brake cylinder thus cut off.Slide valve 45 will continue to blank exhaust port 49, so that thesupply to the brake cylinder will be lapped. The pressure at which thesupply is lapped corresponds to the movement of the brake valve handleI41.

When the brake valve handle MI is moved in the service zone, the brakepipe 14 is maintained connected to the feed valve device I48, throughthe port I10 in the rotary valve I46, so that the parts of the triplevalve section 26 remain in the release position shown in Figure 2.

As the pressure of the fluid supplied to the brake cylinder or brakecylinders increases, the vehicle will begin to decelerate at anincreasing rate. The body I52 in the retardation controller device i6 isthen caused to move to the left. Assuming that the body I52 has beenmoved far enough for movable contact I63 to disengage from contact I86,then slide valve I60 will have been actuated to the right far enough todisconnect pipe 88 from pipe 208, but not far enough to connect pipe 88with exhaust pipe 201.

Dis'engagement of contact I63 from contact I66 opens the circuitpreviously described to the electromagnet controlling the cut-off valveI00 in the right hand magnet valve section 32, nd this valve is seatedby its spring I02. Disconnecting pip-e 88 from pipe 208 closes thecommunication previously described between the maintaining reservoir I08and piston chamber 8|, through the retardation controller device, sothat both the communication by way of the retardation controller deviceand that by way of the right hand magnet valve device 32, from themaintaining reservoir to piston chamber 8!, are closed.

If now the retardation controller body I52 moves to the left far enoughto cause engagement of contacts I84 and I01, then slide valve I60 Willhave been actuated far enough to the right to bring pipe 88 intocommunication with exhaust pipe 201.

Engagement of contacts I64 and I61 energizes the electromagnetcontrolling the release valve I0l, in the right hand magnet valve secton 32, from battery I80 through a circuit which, beginning at thebattery, includes conductor I8I, connector I05, contacts [64 and I61,conductor I91, the electromagnet, conductor 208, jumper 209 at the endof the vehicle (or train), conductor 2I0, a winding of relay 2, andground connection ZIZ.

Asa result of energizing this electromagnet release valve IOI will beunseated to establish a communication between piston chamber 8i and theatmosphere, by way of restricted port I09,

which restrictsthe rate of release. When the retardation controllerslide valve H6 connects pipe 88 with exhaust pipe 201, a secondcommunication between the piston chamber 8! and the atmosphere isestablished, by way of pipe and passage 89, pipe 88, slide valve I80,and exhaust pipe 201, which has a restriction 2I3 therein to alsorestrict the rate of release. It will thus be seen that twocommunications are established between piston chamber 8i and theatmosphere, and that even though the means controlling one of thesecommunications should fail the other communication will be adequate torelease fluid under pressure from the piston chamber.

As fluid is released from piston chamber 8|, the pressure in the chamberreduces and piston 84 moves downwardly, first to the position whereslide valve 83 blanks port I99, and if the release is great enough thento the position where slide valve 82 blanks passage 2M and slide valveport 2I4 registers with passage 2I0. In the first case the supply torelay piston chamber 48 is lapped, while in the second case fluid underpressure is released from the relay piston chamber to the atmosphere, byway of passages 200 and 202, slide valve chamber 80, port 2I4, passage2l0, which contains a restriction 2I5, and safety valve device 90;

Assuming that fluid is released from the relay piston chamber 48, theconsequent drop in pressure permits piston 41 to move downwardly farenough for slide valve'45 to uncover exhaust port 46. Fluid underpressure is thus released from the brake cylinder, and as a consequencethe rate of retardation diminishes and retardation controller body I52moves toward the right.

When the body I52 has moved far enough to the right for contact I64 todisengage from contact I61, and for slide valve I60 to blank exhaustpipe 201, the venting of piston chamber BI will be terminated. As soonas the pressure in relay piston chamber 48; and slide valve chamber 80,drops by a sufiicient amount spring 88 will actuate piston 84 upwardlyfar enough for g aduating valve 83 to blank port 2I4. Relay piston 41 wll then move to lap position, where slide valve 45 blanks exhaust port46.

If the rate of retardation should then again increase so that body I52 sagain moved to the left, the cycle just described will be rep a ed.Regardless however of how many times he cycle may be repeated, therelease of fluid from relay piston chamber 48 will be terminated by thesafetv valve device 90 when the pressure of the fluid has as a conseuence of the release dropped below a predetermined value, correspondingto the setting of the safety valve device.

To effect a release of the brakes at any time, the operator moves thebrake valve handle I4! to release position. In this position the partsof the brake valve device assume the positi ns shown in Figure 3, wherethe electromagnet controlling release valve 51 is again energized, andflu d under pressure is released from relay piston chamber 48 to theatmosphere, through a communication including passage Z00, ball checkvalve 2 I6, which will unseat, double check valve chamber I 90, passageI95, past the unseated release valve 51, and through exhaust port 82. Itis to be noted that this release may be effected regardless of theposition of the slide valve 82 in the pneumatic cut-off and releasevalve section 28, although if port I 99 in slide valve 82 is inregistration with passage 2I1I, the release may be also efiected throughthis communication.

Emergency application When it is desired to effect an emergencyapplication of the brakes, the handle MI of the brake valve device I4 ismoved to emergency position, where the contacts of the brake valvedevice are operated the same as described for a service application,except that spring I36 is now compressed to a maximum degree, and where,in addition, the rotary valve I46 disconnects the brake pipe 14 from therotary valve chamber I45 and reconnects the brake pipe to the atmosphereby way of exhaust port 2I1. The brake pipe is thus vented to theatmosphere to reduce brake pipe pressure in the manner commonly employedin automatic brake systems.

As a consequence of operation of the contacts in the brake valve device,fluid under pressure will be supplied from supply reservoir 38 to thedouble check valve chamber I96 to a maximum degree. At the same time,the reduction in brake pipe pressure will cause triple piston 61 to moveto its extreme uppermost position, where graduating spring 11 iscompressed.

Triple slide valve will then disconnect volume reservoir I15 fromexhaust port I18, and will at the same time uncover passage I16, whichleads to both the volume reservoir J15 and the double check valvechamber I96, the communication to the double check valve chamber beingby way of branch passage 22!]. Fluid under pressure will then flow fromthe auxiliary reservoir 12 to the double check valve chamber I96 also toa maximum degree, through a communication including pipe and passage 13,slide valve chamber 63, passages I16 and 220.

It will thus be seen that fluid under pressure will be supplied todouble check valve chamber I96, above double check valve I91, from theauxiliary reservoir, while fluid will be also supplied from the supplyreservoir to the underside of double check valve I91. The fluid whichpredominates in pressure will therefore urge the double check valve I91to one side and will then flow through the communication beforedescribed to the relay piston chamber 48. Thereafter the funtioning ofthe parts will be as described for a service application.

The retardation controller device I6 and the pneumatic cut-on andrelease valve section 28 will thus be seen to control both service andemergency applications so as to prevent the rate of retardation fromexceeding a chosen value.

To efiect a release of the brakes following an emergency application,the'brake valve handle I4! is turned back to release position, where thebrake pipe 14 is again connected to the feed valve device M8, andpressure in the brake pipe restored. Triple piston. 61 will thenbeactuatedto its lowermost position, where volume reservoir 11.5 is againconnected to discharge port H18 by cavity I11. At the same time,application valve will be seated and release valve 51 unseated, so thatfluid under pressure will be released from relay piston chamber 46, asbefore described.

The purpose of providing the volume reservoir H5 is to add additionalvolume to relay piston chamber 68. If this additional volume were notprovided, a light reduction in brake pipe pressure would cause a heavyapplication of the brakes. Therefore, in order that the brakeapplication for a given brake pipe reduction shall correspond verynearly to that effected for a similar application in standard brakesystems, additional volume must be added to the system.

Auxiliary service application If for any reason the electropneumatic, orstraight air, portion of the equipment described should be renderedinoperative, a service application of the brakes may be effected byautomatic operation. The brake valve handle MI is then turned toemergency position and left in this position only long enough to ventthe brake pipe according to the degree of brake application desired.Thereafter, the brake valve handle is turned to lap position. Triplepiston 61 will be then actuated upwardly until it engages graduatingstop 15, where slide valve 65 brings its port ZIB in registration withpassage I16, and graduating valve 66 uncovers the port 2I8. Fluid underpressure will then be supplied from the auxiliary reservoir to the relaypiston chamber &8 until equalization takes place on either side oftriple piston 61, whereupon the piston will move downwardly to theposition'where graduating valve 66 blanks port M8. The supply of fluidto the brake cylinder by the relay valve section 22 will then be lappedas a result.

While the retardation controller device and pneumatic cut-01f andrelease valve section 28 are operable to control such auxiliary serviceapplications, such applications will in general be to a degree belowthat required to produce the maximum rate of retardation. If however therate of retardation should increase to the point where the retardationcontroller device effects operation of the pneumatic cut-off and releasevalve section 28, the functioning will be as before described for aservice application.

A release of the brakes may be effected following an auxiliary service.application in the same manner as eflected following an emergencyapplication.

Operation 0 indicating means When the retardation controller device i6has functioned to disengage contact I63 from contact its contact 222 todeenergize indicating device I8. I

The operator is therefore informed that the cutoff valve IE9 is seated.

When contact I64 engages contact I61, of the retardation controller I6,relay 2II will be energized in series with the electromagnet controllingthe release valve Ifil. Relay 2 then closes its contacts 223 to energizeindicating device 26. The operator is then informed that release valveliil is unseated.

As the retardation controller device reverses this operation of itscontacts, the signaling devices and it will be deenergized andenergized, respectively, to indicate to the operator the functioning ofthe release and cut-off valves aforementioned.

' It is to be noted that the two relays I89 and Eli are each connectedto their associated electromagnet through circuits which extend to theend of the vehicle, or to the end of a train in the case of a number ofcars, and then back to the head end car, so that these control circuitsare checked by the indicating devices, that is to say, the indicatingdevices indicate whether or not the retardation control circuits areintact, and as a consequence whether or not devices connected in thesecircuits are energized or deenergized.

In adapting the embodiment described to a train comprising a number ofcars, it will be readily apparent that only the control valve deviceIll, and the reservoirs and brake cylinder connected thereto, need besupplied on other than the head end or control car.

While I have described my invention with respect to one embodiment, itis to be understood that I do not intend to be limited to thisembodiment or otherwise than by'the spirit and scope of the appendedclaims.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is: 1

1. In a vehicle brake system, in combination, a brake cylinder, relayvalve means for supplying fluid under pressure to the brake cylinder, avalve device operated upon a decrease in pressure to effect operation ofsaid relay valve means to release fluid under pressure from the brakecylinder, a retardation controller device operated according to the rateof retardation of the vehicle, and means responsive to operation ofsaidretardation controller device at a predetermined rate of retardationfor decreasing the pressure in said'valve device.

2. In a vehicle brake system, in combination, a brake cylinder, meansfor supplying fluid under pressure to the brake cylinder, a valve devicehaving a chamber normally charged with fluid under pressure and operableupon a decrease of pressure in said chamber for effecting a release offluid under pressure from the brake cylinder, a first valve operable todecrease the pressure in said chamber, a second valve also operable todecrease the pressure in said chamber, and means responsive to operationof said retardation controller device for controlling both of saidvalves.

3. In a vehicle brake system, in combination, a brake cylinder, meansfor supplying fluid under pressure to the brake cylinder, releasingmeans operable to effect a release of fluid under pressurefrom the brakecylinder, a first valve having a biased position and operable to anotherposition to cause said releasing means to effect a release of fluidunder pressure from the brake cylinder, a second valve also having abiased position and operable to another position to also cause saidrelease means to eifect a release of fluid under pressure from the brakecylinder, and

pressure in said chamber to effect a release of fluid under pressurefrom the brake cylinder, means for establishing a communication fromsaid chamber to the atmosphere, a first valve controlling saidcommunication, means for establishing a second communication from saidchamber to the atmosphere, an electrically operated valve device forcontrolling said second communication, a retardation controller deviceoperated according to the rate of retardation of the vehicle, and meansfor efi'ecting operation of said two valves to open both of saidcommunications in response to operation of said retardation controllerdevice at a chosen rate of retardation.

5. In a vehicle brake system, in combination, a brake-cylinder, meansfor supplying fluid under pressure to the brake cylinder, a valve devicehaving a chamber and operable upon a decrease of pressure in saidchamber to eifect a release of fluid under pressure from the brakecylinder, a normally charged reservoir, means for establishing twodiiferent communications from said reservoir to said chamber, a firstvalve controlling one of said communications, a second valve controllingthe other of said communications, a retardation controller deviceoperated according to the rate of retardation of the vehicle, and meansresponsive to operation of said retardation controller device at achosen rate of retardation for actuating both of said valves to closeboth of said communications.

6. In a vehicle brake system, in combination, a brake cylinder, meansfor supplying fluid under pressure to the brake cylinder, a valve devicehaving a chamber and operable upon a decrease of pressure in saidchamber to efiect a release of fluid under pressure from the brakecylinder, a normally charged reservoir, means for establishing twodifferent communications between said reservoir and said chamber, afirst valve normally opening one of said communications and mechanicallyoperable to close said one communication, a second valve device normallyopening said second communication and operable electrically to closesaid second communication, a retardation controller device operatedaccording to the rate of retardation of the vehicle, and meansresponsive to operation of said retardation controller device at achosen rate of retardation for effecting closing of both of said valves.

'7. In a vehicle brake system, in combination, a brake cylinder, meansfor supplying fluid under pressure to the brake cylinder, a valve devicehaving a chamber and being operable upon a decrease of pressure in saidchamber to efiect a release of fluid under pressure from the brakecylinder, a normally charged reservoir, means for establishing twodifferent communications from said reservoir to said chamber, a firstvalve controlling one communication, a second valve controlling theother communication, means for establishing two other and diiferentcommunications for releasing fluid under pressure. from said chamber,valve means controlling said two release communications, a retardationcontroller device operated according to the rate of retardation of thevehicle, means responsive to operation of said retardation controllerdevice at one rate of retardation for causing said first and secondvalves to close said first two communications, and means responsive tooperation of said retardation controller device at a higher rate ofretardation for causing said valve means to open said two releasecommunications.

8. In a vehicle brake system, in combination,

a brake cylinder, means for supplying fluid under pressure to the brakecylinder, a valve device having a piston subject on one side to pressurefrom a chamber and operable upon a decrease of pressure in said chamberto effect a release of fluid under pressure from the brake cylinder, anormally charged reservoir, means for establishing a first communicationfrom said reservoir to said chamber, a valve having two operativepositions and operable in the first of said positions to close saidfirst communication, means for establishing a second communication fromsaid reservoir to said chamber, an electrically operated valve deviceoperable to close said second communication, means for establishing athird communication through which fluid under pressure is released fromsaid chamber, a second electrically operated valve device operable toopen said third communication, means operable when said first mentionedvalve is in said second operative position to establish a fourthcommunication from said chamber to the atmosphere, and a retardationcontroller device for controlling said first mentioned valve and saidtwo electrically operated valve devices.

9. In a vehicle brake system, in combination, a brake cylinder, meansfor supplying fluid under pressure to the brake cylinder either bystraight air operation or by automatic operation, a valve deviceoperable to effect a release of fluid under pressure from the brakecylinder whether supplied by straight air operation or by automaticoperation, means for establishing a first control communication, meansfor establishing a second control communication, means for maintainingsaid two control communications charged with fluid under pressure, meansoperable upon the decrease of pressure of fluid in said two controlcommunications for causing said valve device to operate to .efiect arelease of fluid under pressure from the brake cylinder, and meansoperated according to the rate of retardation of the vehicle forcontrolling the pressure of fluid in said two control communications.

10. In a vehicle brake system, in combination, a brake cylinder, meansfor supplying fluid under pressure to the brake cylinder either bystraight air operation or by automatic operation, means for establishinga first control communication, means for establishing a second controlcommunication, a valve device operable only upon decrease of pressure inboth of said communications for eflecting a release of fluid underpressure from the brake cylinder, means for supplying fluid underpressure to both of said communications to maintain said communicationscharged, a valve having a first operative position in which the sup plyto one communication is cut off and a second operative position in whichfluid under pressure is released from that communication, twoelectrically operated valve devices one of which is operable to cut oiTthe supply to the second control communication and the other of which isoperable to release fluid under pressure from said second communication,and means operated according to the rate of retardation of the vehiclefor controlling said valve and said two electrically operated valvedevices.

11. In a vehicle brake system, in combination, a brake cylinder, a relayvalve device operable to control the supply of fluid under pressure toand its release from said brake cylinder according to the pressure offluid supplied to said relay Valve device, means for establishing acommunication through which fluid under pressure is supplied to operatesaid relay valve device, means for supplying fluid under pressure tosaid communication either by straight air operation or by automaticoperation, a valve device normally maintaining said communication openand operable to close said communication to either of said supplies andto vent said communication to the atmosphere, two controlcommunications, means for maintaining said two control communicationscharged with fluid under pressure, a valve operable to reduce thepressure of fluid in oneof said control communications,electroresponsive valve means operable to reduce the pressure of fluidin the other of said control communications, means whereby a reductionof pressure of fluid in both of said control communications effectsoperation of said valve device to close said first communication and tovent said first communication to the atmosphere, an element having anormally biased position and operable to one or more control positions,means for controlling saidvalve and electroresponsive valve meansaccording to position of said element, and means for operating saidelement according to the rate of retardation of the vehicle.

12. In a vehicle brake system, in combination, a brake cylinder, a relayvalve device operable to control the supply of fluid under pressure toand its release from the brake cylinder, means for establishing a-firstcommunication through which fluid under pressure is supplied to operatethe relay valve device, means for supplying fluid under pressure to saidfirst communication, means for establishing a second communicationleading to the atmosphere, a valve device normally maintaining saidfirst communication open to said supply and operable to close said firstcommunication to said supply and to connect said first communication tosaid second communication, a retardation controller device having a normally closed contact and a normally open contact, means responsive toopening of said normally closed contact and closing of said normallyopen contact for causing said valve device to operate to first closesaid first communication to said supply and to then connect said firstcommunication to said second communication.

13. In a vehicle brake system, in combination, a brake cylinder, a relayvalve device for controlling the supply of fluid under pressure to andits release from the brake cylinder, means for establishing acommunication through which fluid under pressure is supplied to operatethe relay valve device, a second valve device controlling saidcommunication and operable upon a decrease in pressure to close saidvcommunication, means for establishing a by-pass communication aroundsaid second valve device, a third valve device operated upon apredetermined increase in pressure for closing said by-passcommunication, and

trol communications charged with fluid under pressure, a valve operableto a first position to close one of said control communications to saidcharging means and operable to a second position to reduce the pressurein that control communication, a normally energized magnet valve deviceoperable when deenergized to close the other of said two controlcommunications to said charging means, a normally deenergized secondmagnet valve device operable when energized to reduce the pressure insaid second control communication, a valve device responsive to pressureof fluid in said two control communications and operable upon a decreasein pressure of fluid in both of said control communications forefiecting a release of fluid under pressure from the brake cylinder, andmeans operated according to the rate of retardation of the vehicle forcontrolling said valve and energization of said two magnet valvedevices.

15. In a vehicle brake system, in combination,

a brake cylinder, means for supplying fluid under pressure to the brakecylinder, a valve device having a piston subject on one side to pressurefrom a chamber and on the other side to pressure corresponding to brakecylinder pressure and operable upon a decrease of pressure in saidchamber to release fluid under pressure from the brake cylinder, meansfor supplying fluid under pressure to said chamber through a pluralityof communications, a retardation; controller device having normallyclosed contacts adapted to be opened at one rate of retardation andnormally open contacts adapted to be closed at a higher rate ofretardation, means responsive to opening of said normally closedcontacts for closing one of said communications to said chamber, andmeans responsive to closing of said normally open contacts forestablishing a communication between said chamber and the atmosphere.

16. In a train brake system, in combination, a brake cylinder for eachcar in the train, a supply reservoir for each car in the train, meansfor each car in the train for controlling the supply of fluid underpressure from a supply reservoir to a brake cylinder on that car, aretardation controller device operated according to the rate ofretardation of the train for the head end car, means including twomagnet valve devices for eachcar in the train for controlling therelease of fluid under pressure from the brake cylinder on that car,circuits extending from said retardation controller device on the headend car to the rear car in the train and then back to the head end car,the magnet valve devices on each car being connected in said circuits,and indicating means on the head end car associated with each of saidcircuits and operable to indicate when said circuits are energized anddeenergized.

1'1. In a train brake system, in combination, a brake cylinder, acontrol valve device for controlling the supply of fluid under pressureto and its release from said brake cylinder, said control valve devicehaving a plurality of magnet valve devices associated therewith forcontrolling the pressure of fluid supplied to said brake cylinder, aretardation controller device having contacts operated at chosen ratesof retardation, a plurality of indicating devices, and circuits forconnecting each of said magnet valve devices in series with a differentone of said indicating devices and to said contacts.

18. In a vehicle brake system, in combination, a brake cylinder, acontrol valve device for controlling the supply of fluid under pressureto and its release from said brake cylinder, said control valve devicehaving two magnet valve devices for controlling the release of fluidunder pressure from the brake cylinder, a retardation controller devicehaving contacts operable at different rates of retardation, a pluralityof relays, circuits for

